Add backup and restore scripts for migrating user data between PCs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/backup-data.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+# Backs up user data to a timestamped zip file you can copy to your new PC.
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+APP_DIR="$(dirname "$SCRIPT_DIR")"
+DB_FILE="$APP_DIR/server/data/projects.db"
+TIMESTAMP=$(date +"%Y%m%d_%H%M%S")
+BACKUP_FILE="$APP_DIR/study-app-backup_$TIMESTAMP.zip"
+
+if [ ! -f "$DB_FILE" ]; then
+  echo "ERROR: Database not found at $DB_FILE"
+  exit 1
+fi
+
+zip -j "$BACKUP_FILE" "$DB_FILE"
+
+echo ""
+echo "Backup created: $BACKUP_FILE"
+echo ""
+echo "Copy this file to your new PC, then run:"
+echo "  scripts/restore-data.sh <path-to-backup-file>"